渤海辽北地区走滑转换构造发育特征及其对圈闭样式的控制作用

Development and cycle control of strike-slip transition zone in Liaobei area of Bohai Sea

基于渤海辽北地区钻井资料和三维地震资料精细解释,对走滑断裂发育特征开展精细研究,并进一步完成对走滑转换构造的宏观判识和精细刻画,总结走滑转换构造对圈闭样式的差异控制作用。研究结果表明:①辽北地区断裂体系整体表现出强烈的右旋走滑性质,在走滑断裂叠接带、弯曲、尾端等构造位置,因构造应力调整而发育大量走滑转换构造;②依据走滑转换带的力学性质划分为增压型和释压型2大类,每一大类依据断裂空间展布关系进一步细化为单支弯曲型和双支叠复型,其中,单支弯曲型表现为单条走滑断层平面呈现“S”型变形,双支叠复型则表现为右旋左阶或右旋右阶;③增压型和释压型走滑转换构造控制发育的圈闭类型分别以断背斜和断块构造圈闭为主,增压型走滑转换构造控制的圈闭相对于释压型具有更大的勘探潜力。该研究丰富了走滑转换构造体系,填补了辽北地区走滑转换构造研究的空白,对渤海海域郯庐走滑断裂带油气勘探具有一定的借鉴指导意义。

Combined with previous research results based on three-dimensional seismic data and drilling data,the development characteristics of strike-slip faults in the northern Liaoning,NE China,was analyzed in detail,the macro identification and fine characterization of strike-slip transition zone were completed,and the role of strikeslip transition zone in controlling the development circling was summarized.Results show that the Dongying fault system as a whole shows clear dextral strike-slip properties.Three NE-trending strike slip faults are developed,and the fault assemblages present typical strike-slip structural styles,such as feather,echelon,horsetail,and flower.In terms of mechanical properties of strike-slip transition zone,they were divided into two categories:pressurization type and depressurization,and each could be subdivided into two sub-categories according to the spatial distribution relationship of faults:single-branch bending type and dual-branch superposition type.The first type shows that the plane of single strike-slip fault presents"S"type deformation,and the second type shows dextral right-stepped arrangement or dextral left-stepped arrangement.The pressurized and depressurized strike-slip transition zones controlled the development of fault anticline trap and fault block structural trap,respectively;and the former trap has greater exploration potential than the latter.This study enriched the structural system of strikeslip transition zone,filled the gap in the study of strike-slip transition zone in the northern Liaoning,and shall be able to guide the oil and gas exploration in the Tanlu strike-lip fault zone in the Bohai Sea region.